Kebuk Pasuan (Surge Chamber Cavern: SCC) adalah sebahagian daripada
stesen kuasa bawah tanah Projek Hulu Terengganu Hydro Electric (HEP) disediakan
untuk melindungi terowong Tailrace daripada kesan pukulan kerana bebanan turun
naik air; ia terletak di bahagian hilir daripada rumah kuasa dan pelepasan di bawah
tekanan ke terowong panjang Tailrace. SCC mempunyai bentuk D dengan dimensi
lebar 14 m, tinggi 46 m, panjang 65 m dan dibina 200 m di bawah permukaan.
Permasalahannya ialah SCC digali dalam formasi batuan gunung berapi
dicirikan mengandungi kekar, isotropi, homogen, dan bertekanan. Kehadiran
'lengkokan' di bahagian tengah dinding panjang, beberapa kegagalan seperti lampaupecah
secara geologi dan SCC telah dibina tanpa sokongan lapisan konkrit.
Objektif kajian adalah bertujuan pengelasan ciri batuan, sifat mekanik, dan
keadaan tekanan in-situ jisim batuan; menganalisis kesan jisim batuan; dan
membandingkan antara analisis baerangka dan pemantauan akibat perubahan bentuk
daripada SCC. Daripada mengumpulan data tapak , uji makmal dan analisis dengan
perisian Dip, Unwage dan Phase2 untuk analisis secara berangka. Dari kajian ini telah dibuat kesimpulan bahwa kualiti batuan baik, telah mengalami perubahan bentuk digambarkan dibahagian dinding SCC sebagai lengkokan, beberapa lampau-pecah secara geologi / runtuhan dan rayapan. Anjakan maksimum adalah 25.65 mm dibahagian tengah dinding panjang, Puncak anjakan berlaku dalam tempoh penggalian dan masih menerus sebagai rayapan dan bergerak
kurang atau sama dengan 0.05 mm per bulan. __________________________________________________________________________________
The Surge Chamber Cavern (SCC) as part of underground power station in
Hulu Terengganu Hydro Electric Project (HEP) is provided to protect the tailrace
tunnel from water hammer effect due to fluctuation of water. The SCC is located is
located downstream of the powerhouse and discharges in to a single inclined long
tailrace tunnel under pressure. The SCC has D shape with dimension of 14 m span,
46 m high, 65 m length and constructed 200 m under surface.
The problem statements are the SCC was excavated in jointed volcanic rock
formation, homogeneous isotropic, and has stressed; presence of “buckling” at
middle section of long walls; some geological overbreaks and the cavern has
constructed without concrete support (unlined).The objective this study are characterised of rock, mechanical properties, insitustress condition of rock mass; analyse the effect of rock mass properties due to the deformation and to compare between the numerical analysis and monitoring data
due to deformation of SCC. The data collected on site were used to analysis Dip,
Unwedge and Phase2 software for numerical analysis and analysing of displacement
monitoring.From this study, it was concluded that rock mass of SCC classified as a good
rock however it was deformed, it was visualized on site as buckling, some overbreak/collapse and creep, the maximum displacement 26.45 mm on the middleof long-wall. The peak displacement had been happened during excavation period and observing shows the displacement is still continuing as creep, ≤0.05 mm/ month.
Geomechanical influence on rock mass deformation at Hulu Terengganu hydroelectric power surge chamber cavern_ Mochamad Trisugiwo_A9_2017_MYMY